Geometric Model Describing the Banded Morphology of Particle Films Formed by Convective Assembly

Nanoparticle films coated on smooth substrates by convective assembly from dilute suspensions in dip‐coating configuration are known to have discrete film morphologies. Specifically, the film morphology is characterized by alternating bands of densely packed particles and bands of bare substrate. Co...

Full description

Saved in:

Bibliographic Details
Published in:	Chemphyschem Vol. 10; no. 12; pp. 2116 - 2122
Main Authors:	Lee, J. Alex, Reibel, Kayla, Snyder, Mark A., Scriven, L. E., Tsapatsis, Michael
Format:	Journal Article
Language:	English
Published:	Weinheim WILEY-VCH Verlag 24-08-2009 WILEY‐VCH Verlag Wiley
Subjects:	Chemistry Colloidal state and disperse state Exact sciences and technology General and physical chemistry Ion-exchange nanomaterials nanostructures particles Physical and chemical studies. Granulometry. Electrokinetic phenomena self-assembly Surface physical chemistry thin films Zeolites: preparations and properties Monolayer Binary compound Particle size Growth Film Nanoparticle Silica Molecular sieve Mechanism Thin film Particle Dilute suspension assembly Dip coating particles Multilayer Nanostructure nanomaterials Air Zeolite nanostructures Contact line thin films Substrate Morphology self Models
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	Nanoparticle films coated on smooth substrates by convective assembly from dilute suspensions in dip‐coating configuration are known to have discrete film morphologies. Specifically, the film morphology is characterized by alternating bands of densely packed particles and bands of bare substrate. Convective assembly is a frontal film‐growth process that occurs at the three‐phase contact line formed by the substrate, the suspension in which it is submersed, and the surrounding air. The bands are parallel to this contact line and can be either monolayered or multilayered. Monolayered bands result whenever the substrate is withdrawn from the suspension at a rate too high for particles to assemble into a continuous film. We report a new insight to the mechanism behind this banding phenomenon, namely, that inter‐band spacing is strongly influenced by the constituent particle size. We therefore propose a geometric model relating the inter‐band spacing to the particle size. By making banded films with systematically varied particle sizes (silica/zeolite, 20 to 500 nm), we are able to quantitatively validate our model. Furthermore, the model correctly predicts that multilayered banded films have higher inter‐band spacings than monolayered banded films comprising the same particles. Banded particle films: Convective assembly of particles from dilute suspensions can produce discrete film morphologies in the form of bands. The spacing between such bands, when they are in a monolayer, is a strong function of the particle size. A geometric model considering the intersection of the particles with a stretched liquid meniscus can quantitatively predict these spacings with varying particle diameter (see picture).
Bibliography:	NSF Department of Energy - No. DE-FG26-04NT42119 istex:CBBFB065210C713773CD5718DE32AD590DCCDF42 National Science Foundation - No. CTS-0332484 ark:/67375/WNG-6Q51BM16-S National Science Foundation - No. DMR-0754792 ArticleID:CPHC200900127 deceased ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	1439-4235 1439-7641
DOI:	10.1002/cphc.200900127